// In the name of Allah
#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef complex<ld> cld;
#define all(x) (x).begin(),(x).end()
#define len(x) ((ll) (x).size())
#define F first
#define S second
#define pb push_back
#define sep ' '
#define endl '\n'
#define Mp make_pair
#define kill(x) cout << x << '\n', exit(0)
#define set_dec(x) cout << fixed << setprecision(x);
#define file_io(x,y) freopen(x, "r", stdin); freopen(y, "w", stdout);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxn = 2000 + 4;
int n;
string res;
string guess_sequence(int Nx) {
n = Nx;
if (press("AB") >= 1) {
if (press("A") >= 1) res += "A";
else res += "B";
}
else {
if (press("X") >= 1) res += "X";
else res += "Y";
}
vector<char> ls;
for (char ch : {'A', 'B', 'X', 'Y'}) {
if (ch != res[0]) ls.pb(ch);
}
for (int i = 1; i < n - 1; i++) {
string s = "";
s += res; s += ls[0];
s += res; s += ls[1]; s += ls[0];
s += res; s += ls[1]; s += ls[1];
s += res; s += ls[1]; s += ls[2];
int x = press(s);
if (x == len(res) + 1) res += ls[0];
else if (x == len(res) + 2) res += ls[1];
else res += ls[2];
}
if (press(res + ls[0]) == n) res += ls[0];
else if (press(res + ls[1]) == n) res += ls[1];
else res += ls[2];
return res;
}
